Barcode Check Digit Calculator.

This should get you started:

var sVal = "2468135791234"; // Sample value
var sum = 0;
var factor = 3;

for (var i = sVal.length - 1; i > -1; i--) {
sum += +sVal[i] * factor;
factor = 4 - factor;
}

var check_digit = (sum % 10) ? 10 - (sum % 10) : 0;

app.alert(check_digit);

How would I add this to a button.

End user enters 13 digits. hits the button. correct check digit appears in a seperate box beside the entered #

Sorry. I understand how the coding works I'm just unclear on the structuring of the script.

The script should first get the value of the input field, as a string. Then check to see if the number of digits is correct. Then calculate the check digit using code like that previously posted. Then set the value of the check digit field equal to the check digit. Something like:

// Get input field value as string
var sVal = getField("input_field").valueAsString;
var check_digit = "";

// Calculate check digit
if (sVal.length === 13) {

var sum = 0;
var factor = 3;

for (var i = sVal.length - 1; i > -1; i--) {
sum += +sVal[i] * factor;
factor = 4 - factor;
}

check_digit = (sum % 10) ? 10 - (sum % 10) : 0;

} else {

app.alert("Please enter 13 digits!", 1);

}

// Set the check digit field
getField("check_digit").value = check_digit;


My nice formatting will probably get mangled by the forum software, but you should get the idea. Replace the field names in the code above to suit your form.

Perfect!

Thanks George!

Always good to know there are talented people out there who are willing help us inexperienced ones.

CLIFF